‘At a computer conference in Alexandria, Virginia, Stefan Savage, a computer security expert who led the “Sneakey” project, surfed the photo-sharing website Flickr and found pictures that clearly showed peoples’ keys, even if personal information in the shots had been blurred out.

In one demonstration, the team cut duplicate keys after analysing images taken on a mobile phone. In another, they used a telephoto lens to take pictures of a set of keys on a cafe table from the roof of a university building.’